A facial image detecting technology is used in various fields since an adaptive boosting technology has been appeared in the world. The adaptive boosting technology is used in various facial image detecting and searching systems due to detection of a facial image in real time by learning a face in off-line and a high quality facial image detection.
For instance, the adaptive boosting technology is mainly used in products having a facial image detecting function such as CCTV/Digital Video Recorder (DVR), a face recognizing smart camera, a face recognizing mobile phone, a photo-booth, a face recognizing printer and a digital still camera.
Since a method of detecting a facial image requires a number of facial images, a face detection rate does not come in question. However, a post-processing such as face authorization cannot be carried out when facial image detection in a database search or from a single image such as a photograph is failed. And thus, the facial image detection requires high precision. Moreover, a method of detecting a facial image as a result of learning a face in off-line shows a different face detection rate according to whether which learning database is used.
In addition, a method of searching a candidate of a facial image using color information of an image or segmentation of an image is not suitable for detecting a facial image requiring a high face detection rate because the method is dependent on the color information and the color information is influenced by illumination.
Therefore, in a field requiring a high face detection rate like in a single image, there is no time restriction differently from a field of detecting a facial image in real time but a more precise search is required.